What's Hiding in Your Rig?

Posted by Darrell Nicholson at 02:17PM - Comments: (9)

Courtesy of John Koon/Tradewinds Marine Services, Inc.
Courtesy of John Koon/Tradewinds Marine Services, Inc.

This rigging danger is hiding in plain sight. The crew on this this multihull used for day charters in Hawaii stood a few feet away from this cracked toggle on the port backstay while they welcomed tourists aboard. (Photo courtesy of marine surveyor John Koon/Tradewinds Marine Services, Honolulu, HI)

When awakening your boat from its winter slumber a rig check should be high on the list of priorities. Even though the boat has been sitting still, the laws of physics still take their toll. Corrosion is the biggest enemy and the stainless steel components in your rig can effectively hide the insidious advance of this disease. "The Hidden Causes Of Rig Failure," in the May 2015 issue of Practical Sailor offers a bit of a wake-up call for owners of sailboats with rigs of an indeterminate age. But it also offers some of hope. Over the years we’ve published a variety of articles on the hidden risks of stainless-steel hardware—chainplates, tangs, toggles, clevis pins, etc.—important bits that keep our rig from coming down.

Probably the most detailed article on the topic was technical editor Ralph Naranjo’s critique of stainless steel (see Practical Sailor, February 2007 online). Patrick Childress concentrated on chainplate problems, which was behind the causes of his mid-Pacific rig failure (see Practical Sailor, December 2011 online). And various installments of Mailport and PS Advisor have featured readers' experiences with hardware such as snap shackles (See PS Mailport April 2010 online) and questions regarding rigging replacement schedules (see PS Advisor January 2010).

One underlying moral of these stories is that stainless steel can fail without warning, a message that can leave a boat owner feeling helpless. Does this mean that our only resort is to replace anything that raises suspicion? The line between caution and paranoia becomes thin. Fortunately, stainless steel hardware has a long and mostly successful track record on boats, and the warning signs are often apparent. The trick is knowing where to look.

Boat owners can turn to a number of helpful resources that will guide them through an inspection to ensure that their rigs are up to snuff. If your boat was built in the last decade or so, chances are that the boat manufacturer, or the spar company contracted to supply the rig includes service and inspection guidance. For owners of older boats, owners’ associations can be a vital source. Websites or bulletin boards dedicated to Taiwan builders such as Hans Christian, Ta Chiao (Formosa, Island Traders, CT) and Tayana, as well as many U.S.-built boats (like Childress’ Valiant 40) have documented a range of chainplate problems and repairs in detail. Some of these are quite obvious, and will usually turn up in a routine visual inspection, others are not. (Google-search under your boat model and chainplate, for example “Tayana 37 chainplate,” to see what sort of history your boat might have.)

The U.S. Coast Guard Marine Safety Alert, “Sailboat Rigging Dangers,” issued in 2009, has links to a couple of helpful websites. The alert, which was published after a spate of rigging failures on Coast Guard-certified charter catamarans, should be required reading for every sailor, whether he has questions about the integrity of his rig or not.

In the upcoming May issue of Practical Sailor, renowned rigger and sailing writer Brion Toss, explores of rigging failure in finer detail in an excerpt from his forthcoming book, “Rig Your Boat.” Here are just some of the tips that Toss shares.

  1. Follow the load. Follow the path that loads on your rig follow as they are transferred to the hull or deck. Sharp bends, and slack, ill-fitting, or misaligned unions will concentrate loads in one area and increase the chance of failure at these points. Seemingly minor oversights like using an undersized clevis pin on a toggle can lead to premature failure.
  2. Beware of hidden dangers. Many failure points are often physically hidden from view. Crevice corrosion in chainplates, bobstays, and padeyes often starts where the stainless comes into contact with wet wood or core material, or in fiberglass laminate where water has been trapped. The corrosion is often located on the bottom or back side of the hardware, or buried where the fitting passes through the hull or deck. Seemingly innocuous blooms of rust are often a sign of more serious corrosion is hidden in the hull or deck.
  3. Go aloft. If you don’t unstep your mast each season, you or a qualified rigger should go aloft at least once a year to inspect wire, terminals, spreaders, and the hardware and fittings at the top of your mast. You should hire a pro to do a full inspection every six years, and start thinking about wire replacement after 10-12 years—although this can vary greatly according to use and environmental factors. While you’re off the ground, check around mast tangs for signs of slipping. On painted masts, an exposed unpainted area is often a sign that a tang is slipping. Lower swages (see below) are often cited as the most common source of rig failure, but because these are easy to rinse at the dock, they are often in better shape that the upper-level swages.
  4. Inspect swages. Deck-level wire swages are one of the most common sources of failure on saltwater cruisers. Cracks, swelling, or weeping rust stains are a sign that time is running out for this hardware. Although no absolute timetable exists, riggers we have spoken with advise owners to start thinking about wire replacement after 10-12 years.
  5.  Read the instructions. Turnbuckles can only be loosened so far; screw-on Norseman-type terminal fittings need to be correctly assembled and sealed. Neglecting to review the installation guidelines for any component in your rig is asking for trouble.

Bottom line: Some of the so-called hidden dangers of stainless steel hardware and rigging are not so hidden after all, but we need to know what to look for.

If you know of a good source of information on rig maintenance and inspection that you’d like to share, or specific problems that you’ve found on your own boat, drop us an email at practicalsailor@belvoirpubs.com.

Here is one from Selden that several readers have found helpful:


For more rig inspection tips, check out "The Hidden Causes Of Rig Failure," in the May 2015 issue of Practical Sailor.

Comments (9)

Another comment. Anyone going offshore ought consider "safe proofing" their rig with a sturdy forward staysail stay and sturdy running back stays. Most rig failures occur because the Forward or backstay(s) fail. So having redundancy fore and aft provides secondary support. Ditto for having redundant genoa and mainsail halyards that can be used as temporary stay supports when needed. Lastly there is no better indication of whether a boat has been well maintained by a knowledgeable owner than the condition of the rigging and the engine. Both are the "prime movers". All else is secondary.

Peter I Berman
Norwalk, CT

Posted by: Piberman | May 7, 2017 1:28 PM    Report this comment

There is a reason large sailing vessels/yachts to remain within their "classification" are requrired to unset their rigs and have professional riggers check everything.

There is a reason why savvy sailors do not paint their masts. Crevice corrosion cannot be viewed under paint. Several years ago had the paint completely removed from an 82 foot mast of a large sailing vessel that had been well maintained. The amount of crevice corrosion was quite impressive. Yet the paint was fully intact. Areas of special concern at the stressed areas of the gooseneck, spreader ends, masthead and maststep/foot.
Properly maintained aluminum spars will last almost indefinitely. But require periodic inspection by a knowledgeable professional. Not a job for amateurs or casual sailors.

Peter I Berman
Norwalk, CT

Posted by: Piberman | May 7, 2017 1:22 PM    Report this comment

You can get an electronic load cell to check tension on large standing rigging, but it is probably not worth it for one boat, tuned only occasionally. So get a grasp of the principles -- I can recommend Selden's free guide and my not-expensive DVD on the subject. You can get optimal results without gauges.
As for inspection recommendations, where are you hauling your boat? We could continue this conversation on Spartalk, if you like.
Fair leads,
Brion Toss

Posted by: Brion T | April 16, 2015 11:25 AM    Report this comment

A link to Selden downloadable PDF "HINTS AND ADVICE on rigging and tuning
of your Selden mast" which discusses rig tension and is recommended by several readers now appears at the bottom of the blog.

Posted by: sailordn | April 10, 2015 12:28 PM    Report this comment

The link for the Selden spars document is here:


Posted by: bplipschitz | April 10, 2015 11:48 AM    Report this comment


Seldon Spars has an excellent "Hints and Advise" PDF (90 pages of easy to read detail) that covers a no-tool tensioning method (page 32) applicable to all sizes; I've used it up to 1-inch. Sorry, no links are posted here, but it is easy to find.

In a nutshell, you secure a fixed length (2 meter) rule at by one end to the stay and tension until the stay stretches 3mm (the rule is not tensioned and does not stretch). This works because all stranded wire rigging stretches the same amount at the commonly recommended 15% BS pretension.

Many other installation and tuning instructions are included. A great reference.

Posted by: Drew Frye | April 8, 2015 6:13 PM    Report this comment

Friends had the rig drop on their 44' cruising cat, probaly due to a rigging failure. Insurance covered the repairs, which cost more than $150,000.

Posted by: Steven W | April 8, 2015 11:18 AM    Report this comment

I had two failures of same-manufacturer bent toggles at the same spot, ~ 5 years apart. The bending during manufacture leaves enough residual stress to encourage cracking on the outside radius. I caught both as thin cracks (nothing like the picture) during routine inspections. This is not one of my favorite fittings, but at least it is easy to inspect.

Posted by: Drew Frye | April 8, 2015 10:03 AM    Report this comment

I am pulling the rig on my 2001 Beneteau Oceanis 461 in a couple of weeks.
There is no documentation that indicates the rig has ever been pulled previously.
Can you provide any specific recommendations?

Also can you recommend a tension gauge that can go up to 9/16"? Loose does not.

Posted by: Alex C | April 7, 2015 9:24 PM    Report this comment

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